Impact of traditional and innovative malaxation techniques and technologies on nutritional and sensory quality of virgin olive oil – A review

Abstract

Virgin olive oil (VOO) nutritional and sensory quality depends on several aspects, including mechanical extraction technology: in this regard, malaxation conditions play a pivotal role since the major transformations linked to phenolic compounds (PC) and volatile compounds (VC) development and degradation take place during this step. Most of the reported studies state that malaxation should be carried out at temperature ranging 18–27°C for 30–40 min: this allows PC solubilization in the oil phase, the production of secoiridoid derivatives, and the development of aroma-active aldehydes, alcohols, and esters, limiting both PC losses and the generation of undesired VC. Reducing oxygen concentration in the headspace up to 5% helps to preserve the phenolic fraction, but slightly impairs VC generation. The use of pectolytic enzyme preparations and the application of innovative technologies like pulsed electric fields and ultrasound promote cell damages, and thereby the release of enzymes and micro-components. This review prioritizes the importance of further research aimed at defining specific optimization charts for each olive cultivar and maturity level, due to the relevant impact of genetics and agronomical factors. Furthermore, kneading conditions may be defined also depending on the desired quality of VOO, e.g., antioxidant power and/or bitterness level.

Keywords

• VOO
• Phenolic compounds
• Volatile compounds
• Malaxation temperature
• Pulsed electric field
• Ultrasound